Caps were 47uF instead of the 100uf listed in the service manuals. ?Which I suspect lead to them failing or cause issues
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On Mar 12, 2025, at 7:21?PM, Bob via groups.io <W4JFABob@...> wrote:
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What do you mean by "
inappropriate value capacitors"?It’s been a while since I updated, but the repair has been a major challenge.? Finally have a major update.? The radio has been repaired without having to replace any boards.? I bought a new DDS, Logic, and Main, but by the time the new boards would come in, I would find and repair the original.? So, now I have spares.? Onto the results!
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Not Powering on: Dreaded Click-Click was traced to Display Board having inappropriate value capacitors and burned spot next to connector on Main Board.? Replaced capacitors in Display Board and rebuilt the area around the burned spot on main board.? There was a broken/burned trace under the connector.? After this section was done, it powered up.
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Logic board- NO AUDIO.? This was a PAIN.? Found burned inductor L551, replaced.? Still no audio.? Replaced several resistors and capacitors trying to rule out issues along the signal path, no luck.? Replaced IC551 due to a suspicious spot and was in the path of the burned inductor….still nothing.? I pulled my 7000 back out and mapped ALL the signals for the audio circuits I could with an oscilloscope and found NO CLOCK SIGNAL on the CLK circuit.? Traced back to the same connector that was affected on the main board.? R705 on Logic Board had over 10x the resistance it was supposed to.? Replaced it and she is singing again.
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DDS board- no idea.? Seems fine for now, but I will find out when I move onto the alignment.? It said no RX/TX, but it seems like it is receiving.? If I post on this again, then I found a problem.? If not, there was no problem with the DDS unit.
